Physics End of Topic Test

Question 1

How is work done?

Answer 1

Work is done when a force is applied and an object is moved a distance. This transfers energy.

Question 2

How do we calculate work done?

Answer 2

Work Done = Force x Distance

Question 3

How would we define a joule?

Answer 3

1 Joule is the energy transferred when a force of 1 N causes a displacement of 1 m

Question 4

What properties does a moving object have?

Answer 4

A moving object has mass and velocity

Question 5

What is the kinetic energy store of an object?

Answer 5

The kinetic store of an object relates to its motion. The faster an object moves, the more energy it has in its kinetic store.
A moving object also has mass and if a larger mass travels at the same speed it would have more
energy in its kinetic store.

Question 6

How to calculate the Kinetic Energy Store?

Answer 6

Kinetic energy = 1/2 × mass × velocity squared

Question 7

What is the elastic potential energy store of
an object?

Answer 7

The elastic potential store of an object relates to how stretched it is. The more stretched (extended)
it is, the more energy it has in its elastic store.

Question 8

How would we calculate the amount of
energy in the elastic potential store of an
object?

Answer 8

Elastic potential energy = 1/2 × spring constant × extension squared

Question 9

What is the gravitational potential energy
store of an object?

Answer 9

The gravitational potential store of an object relates to how high above the Earth’s surface it is. The
higher it is, the more energy it has in its gravitational potential store.

Question 10

How would we calculate the amount of
energy in the gravitational potential store of
an object?

Answer 10

GPE = mass x gravitational field strength x change in height

GPE = mass x 9.8N/kg x height

Question 11

What is the value of the gravitational field
strength on the Earth and the Moon?

Answer 11

Earth: g = 9.8 N/kg
Moon: g = 1.6 N/kg

Question 12

What is power?

Answer 12

Power is the rate of transferring energy, also considered as the rate of doing work.

Question 13

How would we calculate the power of an
energy transfer?

Answer 13

Power = work done/time

Question 14

How would we define a Watt?

Answer 14

1 Watt is equal to a transfer of 1 joule per second.

Question 15

What does it mean if a kettle has a 3 kW
rating?

Answer 15

This kettle transfers 3000 J of energy to the thermal store of the water in it per second.
This kettle does 3000 J of work to the water in it every second.

Question 16

What is the law of conservation of energy?
How do we apply this law?

Answer 16

Energy cannot be created or destroyed, only stored and transferred.
The total energy output from a device is equal to the total energy input.

Question 17

What do we mean for a device to be
efficient?
If a device is inefficient what does it do?

Answer 17

If a device is efficient it transfers its energy usefully.
If a device is inefficient it loses energy to the surroundings (usually by heating), we call this energy
dissipated or wasted, as it is transferred to less useful stores

Question 18

How do we calculate the efficiency of an
energy transfer?

Answer 18

Efficiency (%) = Useful Output Transfer/Total Input x 100

This equation can be used with both energies and powers.

Question 19

How to calculate speed at ground?

Answer 19

2 x average speed